Tài liệu Oracle Database 11g PL/SQL Programming P2 ppt

Chapter 1: Oracle PL/SQL Overview 15

can also call the FORMAT_CALL_STACK or FORMAT_ERROR_STACK from the same package

to work with thrown exceptions.

The following is a simple example:

DECLARE

local_exception EXCEPTION;

FUNCTION nested_local_function

RETURN BOOLEAN IS

retval BOOLEAN := FALSE;

BEGIN

RAISE local_exception;

RETURN retval;

END;

BEGIN

IF nested_local_function THEN

dbms_output.put_line('No raised exception');

END IF;

EXCEPTION

WHEN others THEN

dbms_output.put_line('DBMS_UTILITY.FORMAT_CALL_STACK');

dbms_output.put_line('------------------------------');

dbms_output.put_line(dbms_utility.format_call_stack);

dbms_output.put_line('DBMS_UTILITY.FORMAT_ERROR_BACKTRACE');

dbms_output.put_line('-----------------------------------');

dbms_output.put_line(dbms_utility.format_error_backtrace);

dbms_output.put_line('DBMS_UTILITY.FORMAT_ERROR_STACK');

dbms_output.put_line('-------------------------------');

dbms_output.put_line(dbms_utility.format_error_stack);

END;

/

This script produces the following output:

DBMS_UTILITY.FORMAT_CALL_STACK

------------------------------

----- PL/SQL Call Stack -----

object line object

handle number

name

20909240 18 anonymous block

DBMS_UTILITY.FORMAT_ERROR_BACKTRACE

-----------------------------------

ORA-06512: at line 7

ORA-06512: at line 11

DBMS_UTILITY.FORMAT_ERROR_STACK

-------------------------------

ORA-06510: PL/SQL: unhandled user-defined exception

You will likely find the FORMAT_ERROR_BACKTRACE the most helpful. It captures the line

where the first error occurs at the top, and then moves backward through calls until it arrives at